Multi-mode multi-pass delay

An optical delay device, comprising:

• a multi-mode waveguide for propagating first light through at least a first portion of the multi-mode waveguide of a first uniform width at least along a first region thereof;
• a first waveguide, wherein at least a first portion of the first waveguide has a second uniform width that is less than the first uniform width, wherein the first waveguide is positioned adjacent to the first region of the multi-mode waveguide for receiving the first light in a first mode from the multi-mode waveguide and coupling the received first light back into the first region of the multi-mode waveguide as second light in a second mode that is different from the first mode;
• a second waveguide having a third width that is less than the first uniform width, wherein the second waveguide is positioned adjacent to the first region of the multi-mode waveguide for receiving the second light in the second mode from the multi-mode waveguide and coupling the received second light back into the first region of the multi-mode waveguide as third light in a third mode that is different from the first mode and the second mode;
• and
• a third waveguide having a fourth width that is less than the first uniform width, wherein the third waveguide is positioned adjacent to the first region of the multi-mode waveguide for receiving the third light in the third mode from the multi-mode waveguide and coupling the received third light back into the first region of the multi-mode waveguide as fourth light in a fourth mode that is different from the first mode, the second mode, and the third mode.